{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98241", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.329Z", "datePublished": "2026-10-06T08:45:11.954Z", "dateUpdated": "2026-10-19T09:16:12.796Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:16:12.796Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: xfrm: use full sockets in local error paths\n\nxfrm6_local_rxpmtu() and xfrm6_local_error() dereference skb->sk as if it\nalways pointed at a full IPv6 socket.\n\nThat is not guaranteed. TCP SYN-ACK skbs can be owned by a\nTCP_NEW_SYN_RECV request_sock while the output path itself is driven by the\nfull listener. If rerouting selects an IPv6 XFRM tunnel route with a lower\nMTU, the local PMTU/error handling path can reach these callbacks with that\nmini-socket still attached to the skb.\n\nThe callbacks then miscast the request socket as a full inet/IPv6 socket and\ncan read beyond the request_sock allocation when they access inet_sock or\nipv6_pinfo state.\n\nResolve the owner with skb_to_full_sk() in both callbacks and bail out when\nno full socket is attached. This matches the surrounding XFRM IPv6 PMTU/error\nlogic, which already reasons about full sockets with skb_to_full_sk()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The fixed xfrm6_local_error() is reached via __xfrm6_output() -> xfrm_local_error() only if a rerouted SYN-ACK exceeds an xfrm tunnel MTU below ~100 bytes; that needs local xfrm/route/netfilter setup. A remote SYN carries no malformed data and can't create this state (IPv4 PMTU floor is 552, xfrm6_tunnel_check_size clamps to 1280).\nAC:L - The attacker builds every precondition: an IPv6-in-IPv4 tunnel-mode xfrm SA/policy, a tiny outer MTU, a LOCAL_OUT reroute, and a TCP listener they connect to. Each SYN deterministically sends a SYN-ACK owned by a TCP_NEW_SYN_RECV request_sock down the !ignore_df && toobig branch.\nPR:L - The needed XFRM_MSG_NEWSA/NEWPOLICY, nftables rules and link MTU changes only need CAP_NET_ADMIN in the netns, which an unprivileged user gets via unshare -Urn; the listener and connect() are ordinary syscalls.\nUI:N - The attacker sets up the namespace and drives the handshake that emits the SYN-ACK themselves; no other user has to do anything.\nS:U - The out-of-bounds access corrupts kernel heap memory in the same kernel that enforces the attacker's namespace; no hypervisor or IOMMU boundary is crossed.\nC:H - xfrm6_local_error() passes the request_sock to ipv6_local_error() as a full IPv6 socket; inet6_test_bit(RECVERR6) reads inet_flags past the end of the tcp6_request_sock allocation, into the next slab object, and the rest of the path keeps reading socket fields out of bounds.\nI:H - If the out-of-bounds RECVERR6 bit is set, sock_queue_err_skb() does atomic_add on an OOB sk_rmem_alloc, links an skb into an OOB sk_error_queue list and calls the OOB sk_error_report pointer: heap writes plus control-flow hijack if the attacker grooms the adjacent object.\nA:H - Treating neighbouring slab memory as sk_error_queue and sk_error_report gives list corruption or a wild indirect call, crashing the kernel; the attacker can repeat it with each SYN." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/xfrm6_output.c" ], "versions": [ { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "b1a88633c36d2cbc3831382f3846754d344276fd", "status": "affected", "versionType": "git" }, { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "904a0e827d0d7189271a3a2eb648293809f25efc", "status": "affected", "versionType": "git" }, { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "675919e08ce266b8cac11fd9af29170e762a480f", "status": "affected", "versionType": "git" }, { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "60459c670329d586a58db5d8f811fa5accfe4862", "status": "affected", "versionType": "git" }, { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "ca3d68c3213475b53db6647e159dc73bd1af5ab1", "status": "affected", "versionType": "git" }, { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "4c030a0400ebfd2318361c923a88103b2c67c49f", "status": "affected", "versionType": "git" }, { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "c21f3f7fbfeda7c5794f606cb0ffcc2d9001eef8", "status": "affected", "versionType": "git" }, { "version": "dd767856a36e00b631d65ebc4bb81b19915532d6", "lessThan": "6973a21ee73c5567f883813c8ef414774b45892f", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/xfrm6_output.c" ], "versions": [ { "version": "3.2", "status": "affected" }, { "version": "0", "lessThan": "3.2", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.271", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.222", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.54", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.8", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "5.10.271" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "5.15.222" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.18.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "7.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b1a88633c36d2cbc3831382f3846754d344276fd" }, { "url": "https://git.kernel.org/stable/c/904a0e827d0d7189271a3a2eb648293809f25efc" }, { "url": "https://git.kernel.org/stable/c/675919e08ce266b8cac11fd9af29170e762a480f" }, { "url": "https://git.kernel.org/stable/c/60459c670329d586a58db5d8f811fa5accfe4862" }, { "url": "https://git.kernel.org/stable/c/ca3d68c3213475b53db6647e159dc73bd1af5ab1" }, { "url": "https://git.kernel.org/stable/c/4c030a0400ebfd2318361c923a88103b2c67c49f" }, { "url": "https://git.kernel.org/stable/c/c21f3f7fbfeda7c5794f606cb0ffcc2d9001eef8" }, { "url": "https://git.kernel.org/stable/c/6973a21ee73c5567f883813c8ef414774b45892f" } ], "title": "ipv6: xfrm: use full sockets in local error paths", "x_generator": { "engine": "bippy-1.2.0" } } } }